Justin Bieber has come under fire from animal charities after posing with a tiger at his father's engagement party.

Peta US (People for the Ethical Treatment of Animals) warned the Sorry singer was "lucky not to have had his throat torn out" after sharing an Instagram snap of him stroking an adult tiger which was tied-up on a leash.

The singer was at a bash thrown for his dad Jeremy and girlfriend Chelsey Rebelo at an estate in Toronto where the hosts had brought in the tiger for entertainment.

And Peta was quick to slam the star for the "cruel and dangerous photo-op", and sent him a letter asking him not to pose with wild animals again.

Peta US senior vice-president Lisa Lange warned: "Justin Bieber is lucky not to have had his throat torn out by this stressed captive tiger.

"This is why Peta urges everyone to stay far away from cruel and dangerous big cat photo ops and also why we're asking Justin to vow that this will be his last time promoting these types of abusive outfits."

But riled-up fans raged against the charity as they defended their idol from the accusations.

I understand that it's upsetting but all Justin did was take a picture with the tiger he's not responsible for this pic.twitter.com/Ee8W1ZeI3U